#ifndef _Nguoi_
#define _Nguoi_
#include <iostream>
#include <conio.h>
using namespace std;
class Nguoi
{
public:
	virtual void Chao();
};
class NguoiViet:public Nguoi
{
public:void Chao();
};
class NguoiAnh : public Nguoi
{
public: void Chao(){
			cout<<"Hello";
		}
};
#endif _Nguoi_